竹材の物理学的性質に関する研究(第IV報) : 收縮の速さの厚さによる差異

概要

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Blocks of dimensions of about a mm.×4〜4.5 mm×30 mm. were sawed from the air seasoned bamboos (Phyllostachys pubescens MAGEL), in which (a) is the tangential breadth as 2,3,4,5,and 6 mm.These blocks were soaked in water until complete y saturated and then exposed to the temperature of 42℃ and the relative humidity of 0.0% in a desiccator.The shrinkage of tangential direction was measured by the dialgauge as it set in the desiccator.(1) The preparatory test, using 2mm. block, which changed the temperature of the soaking block 42℃ to 10℃, shows that the difference of temperature considerably effects on the increasing of shrinkage percentage at the beginning of drying process.(2) Shrinkage percentage when 24 hours elapsed are shown in Table 1.[table](3) The increasing movement of shrinkage percentages, at the beginning of drying process, are not normal parabolic form by the influence of collaps.(4) The more the thickness is, the smaller the shrinkage is in early stage.(5) Next Table 2 shows the times when blocks indicate 1% shrinkage.[table](6) Next formula shows the time when blocks indicate 2% shrinkage.t=8.8^2-28.8x+112.5 t; elapsed time (min.) x; thickness (mm.)(7) Next formula shows the time when blocks indicate 3% shrinkage.t=60・x x; 2,3,or 4 mm. (thickness)t=60・x+60 x; 5,or 6 mm.
日本森林学会の論文
1953-12-25